Research On Reparation Methods Of 35kV Cable With Typical Faults

Along with the continuous improvement of social development and urbanization, a wide range of urban transmission cable lines are laid underground, which can save floor space and improve security. But once the cable line fails, it is difficult to find the fault point and repair the cable. There is no monitoring method which can avoid the development of a cable defect into a cable fault completely, it is impossible to eliminate the cable damage because of external forces. Therefore, once the cable fault occurs, the key issue is how to repair the cable quickly and save repairing materials and costs. According to the existing technology, when a single-phase fault occurs, a new part of the cable is always installed to replace the defective parts, in consideration of three-phase cable insulation integrity, and then the two group of three-phase cable connector should be reinstalled. If a cable with only a single-phase fault is totally replaced by a new one, it not only wastes expensive materials, but also spends more labor and time installing cable connectors and digging the cable hole. Researches which focus on repairing single-phase cable fault can reduce the time and cost of repairing the cable significantly and save materials. New ideas and new approaches to repair the single-phase cable fault are presented in this paper.Some methods of repairing the cable before and after the cable fault were discussed in this paper to compare the deficiencies and limitations. First, based on the structure and the accessory type of 35 kV cable, the advantages and disadvantages of cable accessories, environment adaptability, the common types and reasons of the cable fault were analyzed. Then, the key factors of installing the cable accessories and defects that can thread the cable normal-running were found. Finally, according to the current technology and materials, the above theory was applied to repairing the medium voltage XLPE cables single-phase fault. It is proved effective and could be a promotion for cable reparation. This method can improve repairing speed and reduce outage time, material consumption and labor costs significantly.